Lung‐derived exosomes regulate the function of mesenchymal stem cells and alleviate phosgene‐induced lung injury via miR‐34c‐3p

Abstract Phosgene may induce acute lung injury (ALI) when a person is exposed to it. Mesenchymal stem cells (MSCs) were affirmed to have therapeutic effects on phosgene‐induced ALI. In a previous study, ALI exosomes have been confirmed to promote the proliferation and migration of MSCs. However, the mechanism of this phenomenon is still unclear. MicroRNAs (miRNAs) are essential in the physiological process of cells. In this study, lung‐derived exosomes were isolated from phosgene‐exposed and normal rats, respectively, through ultracentrifugation and cultured MSCs with these exosomes. We found that rno‐miR‐34c‐3p was downregulated in MSCs cocultured with ALI exosomes. MiR‐34c‐3p inhibitor promoted the proliferation and migration of MSCs. Moreover, the dual‐luciferase reporter assay demonstrated that miR‐34c‐3p regulated Janus kinase 1 (JAK1) expression. The miR‐34c‐3p inhibitor also significantly activated the JAK1/signal transducer and activator of transcription 3 (STAT3) signaling pathway. In conclusion, ALI exosomes decrease the miR‐34c‐3p expression levels, influencing MSCs via the JAK1/STAT3 signaling pathway.